THE CHARACTERISTIC OF THE FOOD WEB STRUCTURE AT AQUATIC ORGANISMS COMMUNITY IN SUMMER OVER ZOIGE APLINE WETLAND

Zoige Apline wetland is the largest plateau in the world and plays important roles in the biodiversity conservation, regional and global carbon circulation balance and social sustainable development. In order to understand the relationship of food web structure and the trophic characteristics of aquatic organisms community in Zoige Apline wetland, stable isotopes techniques were used to analyze the carbon and nitrogen stable isotope ratios of different aquatic organisms community at 3 sampling areas in Zoige Apline wetland and calculate 6 trophic structure measurable index in 13C-15N isotopic niche. The result showed that the 13C and 15N values of exogenous nutrition source (land plant) were -28.23- -26.07 and -1.20-5.98 respectively. The 13C and 15N values of endogenous nutrition source POM (POM is short for particulate organic matter and it mainly consisted of algae) were -26.39- -21.17 and -25.37- -24.15 respectively. The 13C and 15N values of aquatic plants were 3.68-6.61 and 3.50-4.01 respectively. The 13C and 15N values of POM had a spatial dependent pattern (P0.05, P0.001). The result of food web structure analysis revealed that the carbon (advantaged land plant around Zoige Apline wetland) played a key role in the foundation of the food web structure for the aquatic ecosystem. The food web trophic level between 2 and 3 implied the instability of the ecosystem structure. The result of isotope measurable indexes demonstrated significant spatial differences among the animal community ecosystem structure of the different sampling areas, which might associated with the developed graziery of Zoige Apline wetland.